<template>
  <div class="todo-footer" v-show="total">
    <label>
      <!-- <input type="checkbox" :checked="isAll" @change="checkAll" /> -->
      <input type="checkbox" v-model="isAll" />
    </label>
    <span>
      <span>已完成{{ doneTotal }}</span> / 全部{{ total }}</span
    >
    <button class="btn btn-danger" @click="clearAll">清除已完成任务</button>
  </div>
</template>

<script>
export default {
  name: 'MyFooter',
  props: ['todos', 'checkAllTodo', 'clearAllTodo'],
  computed: {
    doneTotal() {
      // forEach
      /* let i = 0;
      this.todos.forEach((todo) => {
        if (todo.done) i++;
      });
      return i; */
      // pre 之前的值  current 当前的值
      /* const x = this.todos.reduce((pre, current) => {
        return pre + (current.done ? 1 : 0);
      },0); */
      return this.todos.reduce((pre, todo) => pre + (todo.done ? 1 : 0), 0);
    },
    total() {
      return this.todos.length;
    },
    /*  isAll() {
      // 由于v-model 调用之后会直接引起isAll的值改变，所以使用其他方法
      // return this.doneTotal === this.total && this.total > 0;
    }, */
    isAll: {
      get() {
        return this.doneTotal === this.total && this.total > 0;
      },
      set(value) {
        // console.log(value);
        this.checkAllTodo(value);
      },
    },
  },
  methods: {
    /*   checkAll(e) {
      // console.log(e.target.checked);
      this.checkAllTodo(e.target.checked);
    }, */
    clearAll() {
      this.clearAllTodo();
    },
  },
};
</script>

<style scoped>
/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative;
  top: -1px;
  vertical-align: middle;
  margin-right: 5px;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}
</style>